Two simple things - materials and workmanship. The fabric alone that goes into a first-class suit costs more than the price of a cheap suit, and that's before you factor in the time it takes to make the garment. One sure-fire giveaway of a cheap suit is if it has been glued (or fused) in its construction, rather than hand-stitched. This is particularly noticeable on the lapels: if they feel crispy or crunchy when held between the finger and thumb, it is likely that they have been glued. Aside from looking and feeling less sophisticated, fused suits do not last as long as sewn ones, since the glue tends to bubble after you have dry-cleaned the garment a few times. The best suits are still made in either the US or Europe, and so have to bear higher labour costs. However, in return you get a garment that will last for years if you take care of it, and project an air of sophistication and self-confidence. Look out for brands such as Canali, Gucci, Yves Saint Laurent and Richard James.